Symbian's Horizon: one app store to rule them all?

Mobile app stores are quickly approach "a dime a dozen" status -- they're proliferating among carriers, manufacturers, and platform vendors alike, which is a recipe for consumer confusion and developer discontent. The Symbian Foundation appears to see that writing on the wall, though, introducing its Horizon initiative which seeks to help guide developers through the process and publish good apps to as many different app stores as it takes. Horizon appears to be a complete publishing solution; devs don't even need to necessarily have a completed product to start working with it, all you need is a good idea and Symbian claims it'll be ready and willing to hear you out. To quote the Foundation, "We want every Symbian app to be available online and on devices, through as many of the App Stores as possible," which sounds like a good strategy for a platform that's unquestionably being considered an underdog for the moment. Horizon's already open to signups to a limited number of developers, so put those thinking caps on -- you want to be ready for the Satio, don't you?